首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   532篇
  免费   37篇
医药卫生   569篇
  2023年   6篇
  2022年   11篇
  2021年   15篇
  2020年   9篇
  2019年   11篇
  2018年   12篇
  2017年   6篇
  2016年   6篇
  2015年   13篇
  2014年   22篇
  2013年   17篇
  2012年   17篇
  2011年   23篇
  2010年   20篇
  2009年   7篇
  2008年   13篇
  2007年   18篇
  2006年   21篇
  2005年   14篇
  2004年   15篇
  2003年   37篇
  2002年   24篇
  2001年   25篇
  2000年   26篇
  1999年   21篇
  1998年   4篇
  1997年   9篇
  1996年   7篇
  1995年   8篇
  1994年   4篇
  1993年   3篇
  1992年   15篇
  1991年   18篇
  1990年   12篇
  1989年   10篇
  1988年   7篇
  1987年   13篇
  1986年   6篇
  1985年   8篇
  1984年   3篇
  1983年   6篇
  1979年   5篇
  1978年   12篇
  1977年   1篇
  1974年   1篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有569条查询结果,搜索用时 15 毫秒
21.
Digestive Diseases and Sciences - Enoxaparin, a low molecular weight heparin, has been used to prevent thrombotic events during major surgery without increasing the rate of hemorrhage. On the other...  相似文献   
22.
Nb2 cell is a rat lymphoma cell line that responds to lactogens such as prolactin and human growth hormone (hGH) with an increased rate of proliferation. We explored the relationship between the biochemical events induced by hGH and its derivatives and their receptor binding activities. hGH stimulated RNA, DNA and protein synthesis of Nb2 cells as a function of time. Stimulation of RNA and protein was maximal at 2-3 h and 12 h, respectively, after the addition of hGH. DNA synthesis, measured by the rate of [3H]thymidine incorporation, reached a maximum after 18-h incubation with hGH. Stimulation of DNA synthesis was elicited by hGH in a dose-dependent manner between 0.45 and 45 pmol/l. The activity of the 20 K hGH variant in stimulating DNA synthesis was approx 30% of that of hGH. In contrast, S1-hGH, which lacks a sequence of ten amino acids (140-149) of hGH, showed a 3.2-fold greater activity than hGH. F1 (amino-terminal sequence 1-134 of hGH) was only 0.06% as active as hGH, and the activity of F2 (C-terminal 42 amino acid residue of hGH) was less than 0.01%. Both fragment 1-15 and 32-46 were without effect. The relative potencies of these hGH derivatives in stimulating DNA synthesis were similar to their relative abilities to inhibit [125I]hGH binding to lactogenic receptors on Nb2 cell. Nb2 cells provide a suitable model to study the relationship between receptor binding and the biochemical events induced by lactogens.  相似文献   
23.
In an attempt to elucidate possible mechanism(s) for stimulated arachidonic acid metabolism by phorbol 12-myristate 13-acetate (PMA) and epidermal growth factor (EGF) in porcine thyroid cells, we examined the effects of protein kinase inhibitors, isoquinolinesulfonamide derivatives (H-7 and HA-1004), and cycloheximide. The production of PGE2 stimulated by either PMA or EGF was strongly inhibited by H-7, with an ID50 value of approximately 20 to 25 mumol/L in each case, as well as by cycloheximide, with an ID50 value of less than 0.5 micrograms/mL in each case. In contrast, 100 mumol/L of HA-1004 showed less inhibition of PGE2 production provocated by either PMA or EGF. On the other hand, PGE2 production in basal or stimulated condition by exogenously added arachidonic acid, was inhibited to an even lesser extent by both H-7 and cycloheximide. The EGF- and PMA-stimulated release of 3H-arachidonic acid from the cells was also strongly inhibited by H-7 and cycloheximide. These results suggest an induction of synthesis of some proteins responsible for the release of arachidonic acid, which might be attributed to protein kinase-C activation in arachidonic acid metabolism stimulated by PMA or EGF. Moreover, PGE2 production was potently induced by PMA and slightly by EGF in the cyclooxygenase-inactivated cells by acetyl salicylate pretreatment, which also suggests that both agents might induce the synthesis of cyclooxygenase in cultured porcine thyroid cells, although we did not measure its activity.  相似文献   
24.
This study aimed to evaluate the optimal method for planning computed tomography (CT) for prostate cancer radiotherapy to avoid a dose difference of ≥3% between the actual and planned treatments using multiple acquisition planning CT (MPCT). We calculated the 3-dimensional (3D) displacement error between the pelvic bone and matching fiducial marker on MPCT and cone-beam CT scans of 25 patients who underwent prostate volumetric-modulated arc therapy for prostate cancer. The correlation of the 3D displacement error and the dose difference between planned and actual treatments was calculated using least squares second-order polynomial model. The 3D displacement error showed a moderate correlation with differences between planned and accumulated treatment doses (r = 0.587, p < 0.0001). Moreover, the improvement rate of the minimum 3D displacement error showed a strong correlation with the relative error between each MPCT image (r = 0.793, p < 0.0001). Significant differences were observed between planned and actual treatment doses (p < 0.0001) in the relative 3D displacement errors of <1 mm, 1 to 3 mm, and >3 mm. The 3D displacement error on MPCT (as the selection estimation index for optimal planning CT) is useful for monitoring patient-specific intensity-modulated radiation therapy quality assurance. This new method allows to estimate dose differences from the planned dose before commencing treatment, thereby ensuring high-quality therapy. As radiotherapy quality is critical for patient outcome, these findings may contribute to better management of prostate cancer.  相似文献   
25.
[Purpose] The efficacy of diffusion tensor imaging in the prediction of motor outcomes and activities of daily living function remains unclear. We evaluated the most appropriate diffusion tensor parameters and methodology to determine whether the region of interest- or tractography-based method was more useful for predicting motor outcomes and activities of daily living function in stroke patients. [Subjects and Methods] Diffusion tensor imaging data within 10 days after stroke onset were collected and analyzed for 25 patients. The corticospinal tract was analyzed. Fractional anisotropy, number of fibers, and apparent diffusion coefficient were used as diffusion tensor parameters. Motor outcomes and activities of daily living function were evaluated on the same day as diffusion tensor imaging and at 1 month post-onset. [Results] The fractional anisotropy value of the affected corticospinal tract significantly correlated with the motor outcome and activities of daily living function within 10 days post-onset and at 1 month post-onset. Tthere were no significant correlations between other diffusion tensor parameters and motor outcomes or activities of daily living function. [Conclusion] The fractional anisotropy value of the affected corticospinal tract obtained using the tractography-based method was useful for predicting motor outcomes and activities of daily living function in stroke patients.Key words: Stroke, Diffusion tensor tractography, Activities of daily living function  相似文献   
26.
27.
We evaluated the antialbuminuric advantage of cilnidipine, an N/L-type calcium channel blocker (CCB), compared with L-type CCBs in diabetic patients with normoalbuminuria and microalbuminuria. The study was a multicenter, non-randomized crossover trial. Participants were 90 type 2 diabetic patients exhibiting either normo- or microalbuminuria, and undergoing CCB treatment for ≥6 months prior to study entry. The CCB at the time of entry was continued for the first 6 months (Period 1). Treatment was subsequently switched from cilnidipine to an L-type CCB, or vice versa, for the second 6-month observation period (Period 2). During Period 1, the L-type CCB group showed a significant increase of urinary albumin excretion (UAE) over time, while the cilnidipine group showed no significant elevation. During Period 2, switching of the treatment from the L-type CCB to cilnidipine resulted in significant reduction of the UAE, whereas switching from cilnidipine to the L-type CCB resulted in no significant change in the UAE. This study demonstrated that the antialbuminuric effect of Cilnidipine, but not the L-type CCBs, was sustained even in patients treated for a long time. In addition, the antialbuminuric effect can be anticipated after switching from an L-type CCB to cilnidipine, but not vice versa.  相似文献   
28.

Aims

The renin–angiotensin system (RAS) plays an important role in the pathogenesis of diabetic nephropathy. The aim of the present study was to investigate intrarenal RAS activity in patients with type 2 diabetes (T2DM).

Methods

We measured urinary angiotensinogen, a reliable biomarker of intrarenal RAS activity, in 14 controls without T2DM, 25 T2DM patients without nephropathy, 11 chronic kidney disease (CKD) patients without T2DM and 46 CKD patients with T2DM. Associations between urinary angiotensinogen and clinical parameters were examined.

Results

Compared with the controls, urinary [angiotensinogen:creatinine] were significantly higher in T2DM patients without nephropathy (4.70 ± 2.22 vs. 8.31 ± 5.27 μg/g, p = 0.037). Age, hemoglobin A1c (HbA1c) and fasting plasma glucose correlated significantly and positively with the log{urinary [angiotensinogen:creatinine]} (r = 0.632, p = 0.007; r = 0.405, p = 0.027; r = 0.583, p = 0.003, respectively) in T2DM patients without nephropathy. In contrast, the urinary [angiotensinogen:creatinine] were not significantly different between CKD patients with and without T2DM (22.7 ± 27.8 vs. 33.5 ± 40.8 μg/g, p = 0.740); although they were significantly higher when compared with non-CKD patients. In the CKD patients with T2DM systolic blood pressure, serum creatinine, estimated glomerular filtration rate and urinary [albumin:creatinine] correlated significantly with the log{urinary [angiotensinogen:creatinine]} (r = 0.412, p = 0.004; r = 0.308, p = 0.037; r = −0.382, p = 0.001; r = 0.648, p < 0.001, p < 0.001, respectively).

Conclusions

Our findings indicate that poor glycemic control is significantly associated with intrarenal RAS activity in T2DM patients without nephropathy, and that decreased renal function is significantly associated with intrarenal RAS activity in CKD patients with T2DM.  相似文献   
29.
We quantitatively assessed peripheral and autonomic nerve function in diabetic patients and compared them with various parameters of their diabetic status. Motor and sensory nerve conduction velocity (MCV, SCV), vibratory perception threshold (VPT) and the coefficient of variation of the ECG R-R interval (CV R-R) were measured in 85 diabetic patients aged 20-59 years. These values were compared with those of age-matched healthy subjects. Moreover, in 53 patients, MCV, SCV, VPT and CV R-R were investigated by multivariate analysis in relation to clinical parameters. In diabetics, MCV, SCV and CV R-R were significantly lower and VPT was higher than in age-matched healthy controls. The prevalence of impaired values in diabetics was 70% for VPT in the toe, 60% for SCV, and 55% for MCV, CV R-R and VPT in the finger. Impairments of MCV, SCV, CV R-R and VPT were closely correlated with diabetic retinopathy, proteinuria and duration of disease. Categorical regression analysis (multivariate analysis) revealed that the impairment of conduction velocity was closely related to diabetic retinopathy and to hypo- or areflexia, that the impairment of the vibratory perception threshold was related to ischemic changes in ECG and to hypo- or areflexia, and that the reduction of CV R-R was related to orthostatic hypotension and to proteinuria. These findings suggest that diabetic neuropathy progresses in parallel with other complications, and that it is a heterogeneous syndrome rather than a single entity.  相似文献   
30.
The effect of mouse seminal vesicle fluid (SVF) on blastogenic response of splenocytes to mitogens was investigated. SVF significantly suppressed blastogenic response of splenocytes to concanavalin A and phytohemagglutinin in a dose-dependent manner, but blastogenic response to lipopolysaccharide was suppressed only at low, although significant, levels, even at high concentrations of SVF. Extensive dialysis did not reduce the capacity of SVF to inhibit blastogenesis of splenocytes. For elucidation of the mechanisms of suppression of blastogenic response, interleukin-2 (IL-2)-dependent cells were cultured in the presence of IL-2 and various concentrations of SVF. The presence of SVF did not inhibit the proliferative response of IL-2-dependent cells to IL-2. These results suggest that the suppression of blastogenic response of T lymphocytes to mitogens in seminal plasma is caused by an undialyzable component (or components) derived from seminal vesicle and is attributable to the alteration of receptors for mitogens or of IL-2 receptors that are expressed on stimulation by mitogens.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号